There are biological data that support the theory that the human body's internal time clock is set by natural light conditions, such as the sunrise and sunset. In particular, it is believed that one's internal clock may be set so that at sunrise a person wakes up. Of course, this only works if one sleeps in a room that does not block the natural light with drapes or other means. The natural light phenomenon has been recognized and there have been a number of designs proposed to provide a simulation of increasing light at sunrise. For example, U.S. Published Patent Application No. 2005—0248962 to Searfoss et al. describes a nightlight for phototherapy, which includes an alarm function with a wake up mode which may illuminate slowly or substantially immediately to full brightness. However, many users would prefer an alarm clock that is not also functioning as a nightlight in order to save cost. Also it may be desirable to increase the light intensity in steps.
Another such design is described by U.S. Published Patent Application No. 2006—0064144 to Chen et al. that describes a programmable multifunction table lamp for light therapy; however, this table lamp does not include an alarm function and is not an alarm clock. A lamp may function to provide an increase in light, but many would prefer to have a lamp that is a normal lamp and a separate alarm clock, which allows the user to select any desired lamp and save cost.
Yet another such design is U.S. Pat. No. 5,008,865 to Shaffer et al. that describes a light source with gradually changing intensity that is coupled to an alarm clock. In Shaffer, after the alarm clock wake-up signal is provided, the light intensity emitted by the lamp is slowly, smoothly and gradually increased. This device has the disadvantage of unnaturally awakening the sleeper because the light intensity is increased after the audible alarm. Also it may be more desirable to increase the light intensity in steps.
Another design is U.S. Pat. No. 6,236,622 to Blackman that describes a lamp that has an alarm clock built into the lamp. The lamp can be set to gradually increase the light intensity or sound intensity at a controllable time. While a user may wish to have a lamp that includes an alarm clock, it would be more desirable to have a separate alarm clock, which allows the user to select any desired lamp and reduces the cost of the alarm clock. Also, it may be more desirable to increase the light in steps rather than gradually.
Yet another design is U.S. Pat. No. 7,280,439 to Shaddox that describes a sunlight simulating alarm clock. In Shaddox an alarm clock incorporates a lighting system that, prior to the preset waking time, will emit a light that gradually increases in intensity as it changes the ultraviolet spectrum of light it emits, so as to simulate the rising sun. While Shaddox describes a gradual increase in light, it may be more desirable to increase the light in steps. Another disadvantage is that Shaddox describes a device that appears to be quite cumbersome for a nightstand.
What is needed is an alarm clock that does not have the disadvantages of the prior art while providing a simulated sunrise to gradually awaken the user and set the user's biological clock. The embodiments of the present disclosure answer these and other needs.